Device for hydrodynamically strengthening nonwovens, wovens or knitted fabrics

ABSTRACT

The invention relates to an apparatus for hydrodynamic entanglement of non-wovens, wovens or knits, comprising a basic drum ( 1 ) having a multiplicity of holes ( 4 ), on which basic drum ( 1 ), spaced apart therefrom, there is arranged a structured drum ( 6 ), the spacing between the basic drum ( 1 ) and the structured drum ( 6 ) being arranged to be produced by a plurality of wires ( 5, 5′, 5″, 5′″,  . . . ) which are arranged on the surface of the basic drum ( 1 ) and which are at least in part in material-based connection with the basic drum ( 1 ), the wires ( 5, 5′, 5″, 5′″,  . . . ) being arranged in parallel to one another on the surface of the basic drum ( 1 ), characterised in that the wires ( 5, 5′, 5″, 5′″,  . . . ) are arranged on the surface of the basic drum ( 1 ) at an angle α of from 5° to 45°, preferably 15°, relative to the longitudinal axis of the basic drum ( 1 ).

The invention relates to an apparatus for hydrodynamic entanglement of non-wovens, wovens or knits, wherein a liquid such as, for example, water, is sprayed out from a multiplicity of nozzles against the material for entanglement. The material for entanglement runs over a rotating drum which is permeable to liquid and to which negative pressure can additionally be applied in order to draw off the water under suction.

Customarily, the drum consists of a cylindrical solid basic drum having holes which ensure that a large amount of water flows away. A structured drum is drawn over the basic drum, spaced apart therefrom, which structured drum can have finely perforated openings for entanglement of the fibres but which can also provide the material being processed with a surface structure in the form of a pattern.

A basic drum consisting of a solid cylindrical basic body is known from EP 0223614 B2. Parallel to the longitudinal axis, a multiplicity of grooves or depressions are cut into the basic body by milling so that ridges which taper to a point remain. Many large holes are made in the depressions, ensuring that a large volume of water flows away. A thin structured drum having a multiplicity of finely perforated openings is pushed over the ridges. The structured drum customarily consists of a very thin cylindrical metal plate and is highly susceptible to damage. The ridges accordingly provide a spacing between the finely perforated openings of the structured drum and the holes of the basic drum. When hydrodynamically entangling non-wovens or wovens, intermingling of the fibres is achieved as a result of the fibres being pressed at least in part into the finely perforated openings by means of water jets and intermingled. In the process, only individual fibres enter the large openings in the basic drum, which should not, because of the water flowing away, become blocked. The basic drum shown in this prior art is very onerous to produce, as the individual grooves have to be cut into a solid cylinder by milling.

It is also known to apply to a basic drum a wire, in an annular or helical arrangement, which produces the necessary spacing relative to the structured drum. In that constructional form it is disadvantageous that, when the structured drum is demounted from the basic drum, the washed-off fibres that are located between them cause jamming of the structured drum and basic drum, so that the thin structured drum is damaged.

The problem of the invention is to provide an apparatus for hydrodynamic entanglement of non-wovens, woven and knits which is economical in construction and ensures that liquid flows away reliably.

The invention solves the set problem by means of the teaching of claims 1, 8 and 13; further advantageous embodying features of the invention are characterised by the subordinate claims.

In accordance with the technical teaching according to claim 1, the apparatus for hydrodynamic entanglement of non-wovens, wovens or knits comprises a basic drum having a multiplicity of holes, on which basic drum, spaced apart therefrom, there is arranged a structured drum, the spacing between the basic drum and the structured drum being arranged to be produced by a plurality of wires which are arranged on the surface of the basic drum and which are in material-based connection with the basic drum, the wires being arranged parallel to one another on the surface of the basic drum. The material-based connection with the basic drum can be accomplished in partial manner, for example at spaced-apart points or in sections where relatively long regions between the wire and basic drum are connected to one another, there then following a section without a material-based connection. Furthermore, the material-based connection with the basic drum can be provided over the entire length of the wire. A result of the wires being arranged on the surface of the basic drum at an angle α of from 5° to 45°, preferably 15°, relative to the longitudinal axis of the basic drum is that, in technical co-ordination with the nozzle bars, the sprayed-on liquid is removed very well. In contrast to the prior art, a complete row of water jets does not hit the spacer between the basic drum and the structured drum, causing marked and disruptive rebound of the complete row of water jets, but rather only one water jet at a time. When the structured drum is demounted, washed-in fibres cannot cause clogging and/or jamming between the structured drum and basic drum because the space between the individual wires at the end faces is open and the fibres or dirt particles can be removed by way thereof. The structured drum can be twisted off or screwed off the basic drum as with a very steeply angled thread.

The invention makes possible economical and flexible production of the basic drum, wherein the recesses no longer need to be machined out from a solid cylinder. The material-based connection between the wires and basic drum and/or metal plate makes possible an economical and durable connection which withstands a high degree of impact of liquid from the nozzle bars.

It is advantageous that between two to ten rows of holes can be arranged between the wires, which can be dependent on, inter alia, the diameter of the holes and of the wires. As a result, in dependence on the diameter of the basic drum, an optimal combination is obtained between the number of wires, which keep the structured drum spaced apart therefrom, and the number of holes, by way of which the sprayed-on liquid is removed.

In a preferred embodying form, the at least one wire can have a round, rectangular or contoured cross-section. The production costs and also production methods can be varied in accordance with requirements by means of the wire cross-section.

It is especially advantageous for the at least one wire to have depressions and elevations, which results in liquid flowing away especially well, because the wires do not then form enclosed segments but rather the liquid can flow away over a relatively large circumferential extent of the basic drum.

In an advantageous embodiment, the at least one wire has a diameter of from 0.5 to 5 mm, preferably 1 to 3 mm, especially from 1 to 2 mm. This creates a necessary spacing between the basic drum and structured drum, but without at the same time the cross-section of the wire being so large that holes are covered excessively. By virtue of the preferred round shape of the wires, it is possible, in the case of a large wire diameter, for the holes to be partly covered without the water removal being notably impaired.

In a further advantageous embodying form, the wires are soldered onto the surface of the basic drum. Especially in the case of thin basic drums, this does not give rise to the problem of heat distortion as it does in the case of welding, following which the basic drum has to be straightened out again. Soldering the wires to the basic drum in sections further reduces the heat loading.

In order to close the small gaps which are then formed, in which fibres can become lodged, the basic drum is nickel-plated together with the wires. In addition to the corrosion resistance, the nickel-plating also produces a further connection between the basic drum and the wires.

In an alternative second embodying form, the apparatus for hydrodynamic entanglement of non-wovens, wovens or knits comprises a basic drum having a multiplicity of holes, on which basic drum there is arranged, spaced apart therefrom, a structured drum, wherein in accordance with the invention the spacing between the basic drum and structured drum is arranged to be produced by at least one pin having a head, which is arranged to be fixed in the basic drum. The pins can be very simply inserted and fixed in the basic drum so that the heads provide the necessary spacing relative to the structured drum. It is advantageous that the liquid sprayed on for the purpose of entanglement can distribute itself between the pins over the entire circumferential extent of the basic drum and is removed by way of the holes. Furthermore, the apparatus for hydrodynamic entanglement can be matched in highly flexible manner to customer requirements by means of different pins and by means of the number of pins used.

In a preferred embodying form, the height of the heads is between 1 to 10 mm. Modification of the spacing between the structured drum and basic drum is accordingly more flexible than in the case of the first embodying form having the wire. Especially having regard to the spacings from the holes it is possible to use a variety of small or larger heads.

A shape which is very favourable to flow for directing away the sprayed-on liquid is achieved as a result of the heads having an approximately semi-circular shape.

For the first and second embodying forms, the holes in the basic drum have a diameter of from 2 to 10 mm, preferably from 3.5 to 5 mm. As a result, in dependence on the material being processed, good removal of the sprayed-on liquid can be achieved.

In conformity therewith, the holes have a centre-to-centre spacing of from 3 to 12 mm, preferably from 5 to 7 mm, relative to one another so that sufficient stability of the basic drum and/or of the fabric is ensured.

In a third embodying form of the invention, the spacing between the basic drum and the structured drum is produced by knobs having been introduced into the basic drum by means of a deformation process. In contrast to the first two embodying forms, the basic drum becomes more torsion-resistant and accordingly can be of lighter construction.

In a preferred embodying form, the spacing of the knobs can be between 10 and 30 mm relative to one another. This results in a very open structure between the basic drum and structured drum, by way of which the sprayed-on liquid can rapidly flow away.

It is advantageous for the knobs to have a closed contour so that the fibres do not catch in the holes in the basic drum in the course of hydrodynamic entanglement.

Preference is given to the diameter of the holes being between 3 to 10 mm, preferably 2 to 6 mm, so that having regard to the knob spacings it is ensured that the liquid flows away optimally.

According to the prior art, the basic drum is customarily produced from normal stainless steel, the toughness of which is too great for such a deep-drawing process and which is correspondingly expensive. The possibilities of the deformation process are correspondingly limited, because in the event of excessive deformation the material develops cracks.

In accordance with the invention, in this embodying form, the basic drum is produced from a deep-drawable metal having a high deformation capability and is subsequently provided with a surface coating in order to achieve the required corrosion protection. Nickel can be used as a suitable surface coating, which at the same time has a high degree of resistance to wear. The deep-drawable materials may also include non-rusting steels that are suitable for deep-drawing.

The invention is explained in greater detail hereinbelow with reference to a possible embodying example shown in diagrammatic form.

FIG. 1: is a perspective view of a basic drum according to a first embodying example;

FIG. 2: is a section through a basic drum having different wire shapes;

FIG. 2 a: is a longitudinal section from FIG. 2 along a wire;

FIG. 3: is a perspective view of a basic drum according to a second embodying example;

FIG. 3 a: is a section through a basic drum according to the second embodying example;

FIG. 4: is a section through a basic drum according to a third embodying example.

FIG. 1 shows a basic drum 1, which has on its surface a multiplicity of holes 4. The basic drum 1 can be constructed as a solid cylindrical component or as a component having a plurality of cylindrical supports 3, onto which there is drawn a metal plate 2 or a fabric having a multiplicity of holes 4. In this embodying example, a metal plate 2 is drawn onto two cylindrical supports 3, although only one support 3 is shown. The supports 3 are arranged in the region of the end faces of the basic drum 1 and are constructed to take a mounting means (not shown) at both ends. The wall thickness of the solid basic drum 1 can be between 2 to 10 mm. When a metal plate 2 is used, the wall thickness can be between 1 and 6 mm.

The holes 4 are usually of cylindrical construction and can have a diameter of from 2 to 10 mm, preferably 3.5 to 5 mm. The contour of the holes 4 can also be oval, square or of another shape. Furthermore, the cross-section of the holes 4 can change through the depth of the metal plate 2 and, for example, have a conical shape. The centre-to-centre spacings of the holes 4 can be in the range from 3 to 12 mm, preferably in the range from 5 to 7 mm. In this embodying example, holes 4 having a diameter of 5 mm and having a centre-to-centre spacing of 7 mm are used. The holes 4 can be arranged in a line, arranged at an angle α of, for example, 5° to 45° relative to the longitudinal axis of the basic drum 1. In this embodying example, the angle α is 15° relative to the longitudinal axis of the basic drum 1.

Arranged along this line, on the surface of the basic drum 1 between the holes 4, are wires 5, 5′, 5″, 5′″, which are, over part of or all of their length, in material-based connection with the basic drum 1. The wires 5, 5′, 5″, 5′″ are accordingly arranged at an angle of, for example, from 5° to 45° relative to the longitudinal axis of the basic drum 1 in such a way that, as far as possible, none of the holes 4 are covered by a wire 5, 5′, 5″, 5′″ or, if so, only partly covered. In this embodying example, the angle at which the wires 5, 5′, 5″, 5′″ are arranged between the holes 4 is also 15° , therefore always in between, for example, a row of holes 4. The number of wires 5, 5′, 5″, 5′″ arranged on the surface of the basic drum 1 depends, inter alia, on the diameter of the basic drum 1, on the structured drum 6 mounted on the basic drum 1 and on the material for processing which is to be hydrodynamically entangled. Even though only four wires 5, 5′, 5″, 5′″ are shown here, it is clear that the wires 5, 5′, 5″, 5′″ are arranged at regular intervals around the entirety of the basic drum 1 in order to fix the mounted structured drum 6 at a constant spacing.

In this embodying example the wires are arranged at a spacing relative to one another such that six rows of holes 4 are located between every two wires (5 and 5′; 5′ and 5″; 5″ and 5′″). The wires 5, 5′, 5″, 5′″ are in material-based connection with the surface of the basic drum over part, at least, or all of their length, for example by means of a welding or soldering procedure and/or by surface coating such as, for example, nickel-plating. The wires 5, 5′, 5″, 5′″ can have a diameter of from 0.5 mm to 5 mm, preferably 1 to 3 mm, especially 1 to 2 mm, the diameter of the wires 5, 5′, 5″, 5′″ being dependent on the spacing of the holes 4 relative to one another because as a rule covering of the holes 4 is to be avoided as far as possible, or the holes being only partly covered.

A further preferred embodying form are holes 4 in a triangular arrangement which also at the same time form a row of holes in one line. As a result of the rows of holes being offset relative to one another, three holes accordingly form an equilateral triangle.

However, there are also embodying forms in which the holes 4 have a diameter of, for example, 2 mm and the spacing relative to the structured drum 6 has to be maintained using wires 5, 5′, 5″, 5′″ having a diameter of, for example, 5 mm. In this case it is clear that the wires 5, 5′, 5″, 5′″ do, at least in part, cover the holes 4.

In accordance with FIG. 2, the cross-section of the wires 5 can be round, rectangular or square 5′ or contoured 5″. Of course, other cross-sections such as, for example, triangular, are also possible.

The use of wires 5 of round cross-section makes possible very economical manufacture because wires of round cross-section are standard and can be purchased very economically. Furthermore, these wires can be connected to the metal plate 2 especially well by means of soldering or nickel-plating.

Wires 5′ having a rectangular cross-section are likewise very suitable for the material-based connection because they have a large surface contacting the basic drum 1 or metal plate 2. They can be fixed to the metal plate 2 well, especially by means of induction welding and soldering.

Wires 5″ having a contoured cross-section, for example having an overall rectangular cross-section but with a rounded surface facing the structured drum 6, give the structured drum 6 a high degree of stability because of the better contact surface.

Furthermore, as shown in FIG. 2 a, the use of wires 5′″ having an indented surface, that is to say an alternating spacing away from the surface of the basic drum 1, is expedient. Along its longitudinal extent, the wire 5′″ has alternating elevations 5 b′″ and depressions 5 a′″. As a result, liquid sprayed out from the nozzle bars and onto the material being processed can flow away especially well in the region of the depressions 5 a″. As a result, in the regions between the wires no enclosed segments are formed where the liquid can flow away only through the holes 4 bounded by two wires, but rather the liquid can, over a relatively large circumferential extent of the basic drum 1, distribute better and flow away into those regions which are not at the time being sprayed with water by the nozzle bars. For reasons of clarity, the perforation of the structured drum 6, that is to say its fine holes, is not shown in the illustrations of FIGS. 2 and 2 a.

The invention according to the first embodying example of FIGS. 1 to 2 a makes possible very economical and rapid production of the basic drum 1, the depressions no longer having to be machined out from the solid cylinder. By varying the wire diameter and wire cross-sections, it is possible to match a basic drum 1 to customer requirements in very flexible manner. The material-based connection between the wires 5, 5′, 5″, 5′″ and the basic drum 1 or metal plate 2 makes possible an economical and durable connection which withstands a high degree of impact of liquid from the nozzle bars. The construction of the basic drum 1 from the supports 3 onto which the metal plate 2 with the wires 5, 5′, 5″, 5′″ is drawn makes it possible to produce a light basic drum 1 which can be operated using reduced drive power compared to the prior art.

In accordance with the second embodying example according to FIGS. 3 and 3 a, the basic drum 1 is constructed in the same manner as in the first embodying example. The basic drum 1 has, over its entire surface, a multiplicity of holes 4, only individual regions of which have been shown in the drawing. The basic drum 1 can likewise be constructed as a solid cylindrical component or as a component having a plurality of cylindrical supports 3, onto which there is drawn a metal plate 2 or a fabric having a multiplicity of holes 4. In this embodying example, a metal plate 2 is drawn onto two cylindrical supports 3, although only one support 3 is shown. The supports 3 are arranged in the region of the end faces of the basic drum 1 and are constructed to take a mounting means (not shown) at both ends.

The holes 4 are usually of cylindrical construction and can have a diameter of from 2 to 10 mm, preferably 3.5 to 5 mm. The centre-to-centre spacings of the holes 4 can be in the region of from 2 to 12 mm, preferably in the region of from 5 to 7 mm. In this embodying example there were used holes 4 having a diameter of 5 mm and having a centre-to-centre spacing of 7 mm. The holes 4 in this embodying example are not arranged in a line but rather, preferably, in a six-hole arrangement where six holes 4 are arranged around a hole 4. This makes it possible to accommodate the maximum number of holes 4 on a surface. However, other arrangements of holes 4 are of course also possible, for example in a line as in accordance with the first embodying example. Between the holes, pins 7 are fixed in the basic drum 1 or metal plate 2, which pins 7 can be in form of grooved pins or rivets. The heads 7 a of the pins 7 produce the necessary spacing relative to the structured drum 6, which can be between 1 to 10 mm.

The number of pins 7 relative to the number of holes 4 can be, for example, between one to four pins 7 to seven holes 4, that is to say for every 6-hole structure comprising seven holes one to four pins 7 can be arranged in the basic drum 1 or metal plate 2. In this embodying example too, the pins 7 are so arranged that they do not cover any holes 4. Of course, the number of pins 7 can also be significantly higher or lower.

The semi-circular shape of the heads 7 a results in a shape that is very favourable to flow, wherein the liquid can flow away with little resistance. A further advantage compared to the prior art is that the liquid does not have to flow away through the holes 4 in separate regions or segments but can distribute itself in the entire region between the basic drum 1 and structured drum 6.

It is furthermore advantageous for the basic drum 1—in this embodying example the supports 3 together with the metal plate 2 and the pins 7—to be subjected to surface treatment, for example nickel-plated, so as to avoid the small gaps which are formed between the heads 7 a of the pins 7 and the metal plate 2, in which the fibres of the material being processed can catch. A continuous smooth surface is obtained as a result.

In a third embodying example according to FIG. 4, the metal plate 2 of the basic drum 1 consists of, for example, a steel plate having a wall thickness of from 1 to 6 mm, in which a multiplicity of holes 4 are arranged, between which elevations in the form of knobs 8 have been pressed out from the inside of the basic drum 1. These elevations can be produced with a stamp in the course of metal plate working. Because, in the course of metal plate working, particular radii have to be adhered to during the forming process, the number of knobs 8 for a given height of knob 8 cannot be too large, that is to say the spacings between the knobs 8 are greater than can be attained in the case of the embodiment with the pins 7. In this embodying example, the spacing of knobs 8 relative to one another is between 15 and 30 mm, the holes 4 being arranged between the knobs 8.

The holes 4 are usually of cylindrical construction and can have a diameter of from 2 to 10 mm, preferably 3.5 to 5 mm. The centre-to-centre spacings of the holes 4 relative to one another can be based on the spacing of the knobs 8 relative to one another, with its being possible, for example, for there to be two knobs 8 for one hole 4 or also, alternatively, for one hole 4 to be surrounded by four knobs 8. Of course, the ratio of holes 4 to knobs 8 can be greater or smaller depending on the non-woven or woven to be produced. In this shown embodying form, the diameter of the holes 4 is in the range from 4 to 10 mm. When a plurality of holes 4 are arranged in an area surrounded by four knobs 8, the preferred diameter of the holes is somewhat smaller, for example from 2 to 6 mm.

Because of the tolerances in material deformation, the knobs 8 can have differing heights, which can be evened out by subjecting the basic drum 1, over the circumference of the cylinder, to grinding or turning. The heads of the knobs 8 rounded by the deformation can as a result be removed at least in part. After reducing the height of the knobs 8 by grinding or turning, the remaining height can consequently be between 2 to 10 mm. When reducing the height of the tips of the knobs 8 by grinding or turning, it must be ensured that the knobs have a closed contour, that is to say they are not reduced to the extent that an opening is produced. Depending on the non-woven or woven to be produced, such an opening may be undesirable because fibres of the woven being processed may catch therein and result in partial clogging of the perforated structured drum 6. Here too, surface coating, for example as a result of nickel-plating, is also advantageous, because it is a reliable corrosion protection, and cracks and irregularities in the surface of the basic drum 1 are removed, and the surface, including the sharp edges, is made smooth.

Besides the advantage of economical production, producing the basic drum 1 from a metal plate by deformation also has the advantage that the metal plate 2 is integrally constructed with the elevations. The basic drum 1 is, as a result, more torsion-resistant and can be of lighter construction.

All three embodying forms have the advantage that production is very economical without having to cut depressions or grooves in a solid body by milling. Furthermore, very small spacings between the basic drum 1 and structured drum 6 are possible by simple means and can be rapidly matched, using manufacturing technology, to the characteristics of the material to be processed.

REFERENCE NUMERALS AND LETTERS

-   1 Basic drum -   2 Metal plate -   3 Support -   5 Hole -   5, 5′, 5″ , 5′″, Wire -   5 a Depression -   5 b Elevation -   6 Structured drum -   7 Pin -   7 a Head -   8 Knob -   αAngle 

1. Apparatus for hydrodynamic entanglement of non-wovens, wovens or knits, comprising a basic drum having a multiplicity of holes, on which basic drum, spaced apart therefrom, there is arranged a structured drum, the spacing between the basic drum and the structured drum being arranged to be produced by a plurality of wires which are arranged on the surface of the basic drum and which are at least in part in material-based connection with the basic drum, the wires being arranged in parallel to one another on the surface of the basic drum, characterised in that the wires are arranged on the surface of the basic drum at an angle α of from 5° to 45°, preferably 15°, relative to the longitudinal axis of the basic drum.
 2. Apparatus according to claim 1, characterised in that between two to ten rows of holes are arranged between the wires.
 3. Apparatus according to claim 1, characterised in that the wires have a round, rectangular or contoured cross-section.
 4. Apparatus according to claim 3, characterised in that the wires have depressions and elevations.
 5. Apparatus according to claim 1, characterised in that the wires have a diameter of from 0.5 to 5 mm, preferably 1 to 3 mm, especially from 1 to 2 mm.
 6. Apparatus according to claim 1, characterised in that the wires are soldered onto the surface of the structured drum.
 7. Apparatus according to claim 1, characterised in that the structured drum is nickel-plated together with the wires.
 8. Apparatus for hydrodynamic entanglement of non-wovens, wovens or knits, comprising a basic drum having a multiplicity of holes, on which basic drum, spaced apart therefrom, there is arranged a structured drum, characterised in that the spacing between the basic drum and structured drum is arranged to be produced by at least one pin having a head, which is arranged to be fixed in the basic drum.
 9. Apparatus according to claim 8, characterised in that the height of the heads is between 1 to 10 mm.
 10. Apparatus according to claim 8, characterised in that the heads have an approximately semi-circular shape.
 11. Apparatus according to claim 8, characterised in that the holes in the basic drum have a diameter of from 2 to 10 mm.
 12. Apparatus according to claim 8, characterised in that the holes have a spacing of from 3 to 12 mm relative to one another.
 13. Apparatus for hydrodynamic entanglement of non-wovens, wovens or knits, comprising a basic drum having a multiplicity of holes, on which basic drum, spaced apart therefrom, there is arranged a structured drum, characterised in that the spacing between the basic drum and the structured drum is arranged to be produced by knobs which have been introduced into the basic drum by means of a deformation process.
 14. Apparatus according to claim 13, characterised in that the spacing of the knobs is between 10 and 30 mm relative to one another.
 15. Apparatus according to claim 13, characterised in that the knobs have a closed contour.
 16. Apparatus according to claim 13, characterised in that the diameter of the holes is between 4 to 10 mm, preferably 2 to 6 mm.
 17. Apparatus according to claim 8, characterised in that the holes in the basic drum have a diameter of from 3.5 to 5 mm.
 18. Apparatus according to claim 8, characterised in that the holes have a spacing of from 5 to 7 mm relative to one another.
 19. Apparatus according to claim 1, characterised in that the holes in the basic drum have a diameter of from 2 to 10 mm.
 20. Apparatus according to claim 1, characterised in that the holes have a spacing of from 3 to 12 mm relative to one another. 